The invention is related to the field of household electrical appliances, and more precisely to that of electric toasters. It concerns more particularly an improved toaster equipped with a loading device permitting the transport of slices of bread toward the heating elements.
In a general manner, a toaster has heating means that can operate either by radiation or by conduction.
In the first case, the slices of bread to be toasted come in front of the radiant heating elements and thus receive the quantity of energy necessary for their cooking. In the second case, the slices of bread to be toasted come into contact with the element heating by conduction during a time necessary to obtain satisfactory cooking.
In toasters of simple and traditional design, slices of bread are supplied to the appliance manually, by disposing the slices in appropriate housings. Improvements already proposed to toasters of this type consist in equipping the appliance with automatic loading devices. Due to these loading devices, several slices of bread can be transported successively into the heating zones of the toaster in front of which they pass.
A first example of such a toaster is described in the document U.S. Pat. No. 2,714,348. This toaster comprises heating means that include the actual heating elements, and a transport mechanism that permits the transport of slices of toast in front of the heating elements.
This toaster equally comprises a reservoir for slices of bread to be toasted. This reservoir opens in proximity to the heating zone. The bread slices that are stored are delivered progressively under the action of a spring that tends to push the bread slices outside of the reservoir.
This toaster thus presents the advantage of being able to perform in an automatic manner toasting of a substantial number of slices without requiring intervention by the user. However, it presents the major drawback of only operating on perfectly flat slices of bread, of the xe2x80x9ctoastxe2x80x9d type. In effect, the arrangement of the heating means and the geometry of the reservoir cannot in any case be adapted to bread slices of a certain thickness or that present varied forms.
In addition, the pressure exerted on the slices by the spring located at the bottom of the reservoir is a source of crushing of the bread slices, which is prejudicial to good cooking and to the appearance of the toasted bread.
There has also been proposed another type of automatic toaster in the document GB 2 308 291. Such a toaster has horizontal heating elements in front of which circulates a conveyer belt. This toaster is equally equipped with a cylindrical reservoir having multiple radial housings intended to receive bread slices. This reservoir or loader is disposed above the heating elements and can be driven in rotation. During this rotation movement, each housing passes at the base of a slot within which the bread slice falls under gravity onto the conveyer belt. Thus, in proportion with the rotation of the loading reservoir, the totality of slices are transported to the destination of the heating means and then toasted.
Such a toaster has the advantage of assuring an automatic operation, but it presents equally the drawback of being particularly sensitive to the geometry of the bread slices which must, of necessity, pass through slots formed under the loading reservoir. In other words, this toaster does not permit the toasting of slices having relatively large dimensions or of varied geometries.
The object of invention is to propose a toaster that assures an automatic feeding of the heating means starting from a substantial number of bread slices prepared for this purpose and that are insensitive to the size and the general form of the slices to be toasted.
The invention thus concerns an automatic toaster that comprises:
heating means in front of which pass the bread slices to be toasted;
means for transporting the bread slices toward the heating means.
According to the invention, this toaster is characterized in that the means for transporting the bread slices toward the heating means comprise a rotatable element following a spiral form, defining a plurality of housings for the bread slices, said housings having a length corresponding substantially to the pitch of the spiral.
Stated in other terms, the toaster has a loader forming a sort of screw between the turns of which can be placed the different slices of bread to be toasted. When the spiral turns about its axis, the different turns are displaced while carrying the bread slices in the direction of the axis of the spiral. The bread slices are thus transported into proximity of the heating means due to the rotating element that forms a type of Archimedes screw. Such a screw in the form of a spiral is relatively insensitive to the dimensions of the slices of bread to be displaced, which thus permits it to be adapted to different types of bread or at least different slice geometries,
It will be recalled that the geometric definition of a spiral is a curve whose tangents form a constant angle with a given direction. In the case of a circular spiral, corresponding to the case where the spiral is included in a cylinder of revolution, the spiral is characterized by its axis and its radius, its direction of rotation and its pitch that corresponds to the constant length that separates two consecutive points of intersection of the curve with a fixed generatrix situated on the cylinder.
Complementarily, the heating means include means for conveying the bread slices in succession. In this manner, after having been transported by the characteristic loader, the bread slices are positively driven one after the other in contact with or facing the actual heating elements.
In practice, the movement of the bread slices in succession in front of the heating elements can be effectuated either vertically or horizontally.
Thus, when the movement in succession is horizontal, the bread slices are transported by the characteristic loader on a lateral side of the heating means, then taken up by these latter. Inversely, when the movement of the bread slices in succession is effected vertically, the characteristic loader displaces the bread slices to be toasted until coming into proximity to the top of the heating means.
Then, the slices are displaced vertically by the means for passage in succession, after possibly a slight displacement by gravity.
In a preferred form, the characteristic axis of the spiral is inclined in a horizontal plane at a non-zero angle xcex1 with respect to a perpendicular to the plane of passage of the bread slices into the heating means. Stated in other terms, due to this arrangement, the bread slices leave the loader while being oriented in an optimal manner in order to penetrate into the interior of the heating means.
More precisely, the angle xcex1 formed by the axis of the spiral can be deduced from the pitch and the radius of the spiral, as well as the thickness of the bread to be toasted.
According to another characteristic of the invention, when the passage of the slices into the heating means is effectuated vertically, the axis of the spiral can advantageously be inclined in a vertical plane, by a non-zero angle xcex2 with respect to the horizontal. This angle is oriented in such a manner that the axis of the spiral is oriented toward the top in the direction of advancement of the bread slices. In this manner, the bread slices present in the loader are given a vertical inclination such that sliding toward the heating means is optimized. In effect, it is appropriate to avoid that the bread slices tilt toward the front when they leave the characteristic spiral.
Advantageously, in practice one can also provide at the level of the feeding means, an abutment situated at the end of the rotatable element, able to prevent tilting of the bread slices when these latter reach the end of the rotatable element.
Thus, any unexpected movement of the bread slices toward the front, which could provoke them to drop outside of the heating means, is prevented.
In an advantageous form, the toaster according to the invention can also have means for stocking bread slices coming from a heating means or for displacing them toward a receptacle. The bread slices are then displaced from their outlet from the heating means toward a zone intended for their collection.
In a preferred form, the means utilized for stocking or displacing the slices toward the receptacle in question are formed by a second spiral shaped rotatable element. Stated in other terms, when the bread slices leave the heating means, they come to be placed in the housing formed between the different turns of a second spiral. These slices are then possibly transported toward the outlet receptacle. As for the inlet loader, the orientation of this second spiral can be optimized in order for the bread slices to be placed in these housings while remaining parallel to their orientation in the heating means.
Different variants of the heating means can be employed in the toaster according to the invention.
Thus, in a first variant, these heating means can comprise at least one radiant heating element, and a conveyor able to transport the bread slices in front of this heating element. Advantageously, the heating means include at least two heating elements situated at each side of the bread slices to be toasted.
According to another variant, the heating means can comprise at least one heating roller with which the bread slices come in contact, this heating roller being able to convey the bread slices.
Stated in other terms, the heating means comprise several rollers that form a calender between which the bread slices are gripped during their heating.